Xerox Phaser 3450, Service Manual, Page: 144 / 155

11-13
CIRCUIT DESCRIPTION
Service Manual
11.2.3.5 Output Control Circuit
1) Main / Sub Fan
Main Fan and Sub Fan are in-take-type. Main Fan is off
in sleep mode, and Sub Fan operates when printing to
control temperature of inside SMPS.
Main Fan is controlled by TR of Q10 by receiving signal
from U18 18pin, and Sub Fan becomes chopping by
signal of U18 20pin and controlled by TR of Q12.
2) Main Motor
In initial set up stage, Main motor's talk amount about
operating load is set up as BLDC type. It delivers power
for feed device and operation device (Fusing unit is
operated by exit motor) Main Motor has driver IC and
su24V/+5V. It sends Start/stop (L operation) and
clock signal to motor unite to operate motor, and its
rotating speed is controlled by clock frequency. Among
controlling signals, start/stop signal controls U18 19pin,
and clock signal controls U18 68pin. If moving current is
high when driving, it maintains speed within 600ms
(standard speed). Current is changed depending on
loading.
3) Exit Motor
Exit motor drives a fuser, and it rotates clockwise or
counterclockwise when simplex or duplex printing is
working.
4) Main / MP Solenoid
Solenoid functions to pick up fed paper from cassette or
MP. Operating time is 150ms. Main solenoid is controlled
by Q4 TR with U27 E23pin signal, and MP solenoid is
controlled by Q5 TR with U27 C24pin signal. Operating
current is under 250mA.
5) Regi Clutch
Regi Clutch functions to separate paper. Clutch prevents
overlapping delivery of fed paper. After passing 500ms,
when paper detects the feed signal, it turns off and
separates papers.
U27 A26 pin signal controls Q6 TR, and operating current
is under 150mA.